... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. February 16, 1999 . The Large and Small of M87 . ... Explanation: The small core of elliptical galaxy M87 appears to be energizing its whole galactic neighborhood. Recent images from the Very Large Array (VLA) of radio telescopes indicate that huge bubbles of hot gas not only exist but are still being created. ... About APOD > . ...

Astronomy Picture of the Day . Help Aldebaran Map the Moon . ... Tomorrow morning, our Moon will pass directly in front of Aldebaran, the brightest star in this picture and in entire constellation of Taurus. A Very Large Array of Radio Telescopes . ... M81 in True Color . ... This is particularly evident in the above close-up of the LMC's edge, which appears about as large as the full moon. ... Mars Pathfinder's Landing Site . ... Where is Mars Pathfinder? ... The Small Cloud of Magellan . ...

M1 image More About M1 Nice Color Picture . ... M16 image More About M16 HST image . ... M31 image More About M31 Nice Color Picture . ... M42 image ; M43 image More About M42/43 Nice Color CCD Picture . M51 image More About M51 Color Image of M51 M51 Supernova . M57 image More About M57 Nice Color CCD Picture Very Deep M57 Image . ... M81 image More About M81 M81 Supernova Ultraviolet Image of M81 More about Ultraviolet Imaging . M82 image More About M82 M82 False Color M82 True Color . ...

... ESO is building what will be the World's largest optical telescope array, The Very Large Telescope (VLT). The VLT Project organisation is responsible for the design and construction of the Unit Telescopes, including enclosures, optics, adapter-rotators and coating unit. ... Unit Telescopes Overview - This page is outdated, an update is in process. ... Secondary mirror (M2 Unit) - This page is outdated, an update is in process. ... Coating Unit - This page is outdated, an update is in process. ...

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

... Today this year's largest group of sunspots will cross the Sun's central meridian. ... The next day, the number of spots in the group reached five, and the day after, on June 2nd, it was possible to count thirteen sunspots on solar disk, which had been clear prior to this. ... This year's two most powerful active areas, which passed across the solar disk at the beginning of May, 2009, are set to appear in the Sun's eastern sector in two days, on June 6th. ...

... The TRACE images may be used without restrictions in publications of any kind. ... These two images, taken on 18 November 2000 at 15:54UT and 16:11UT, respectively, show such an event: the red circle in the image to the left shows a region where many loops are cooling, with bright loop tops (the intensity scales with the square root of the image to reduce the dynamic range). ... See also a collection of images related to the Sun, other cool stars, and solar-terrestrial effects . ... Images | ...

... ATNF Home . ... About ATNF overview . ... Australia Telescope Steering Committee . ... Parkes radio telescope . ... HI in Elliptical Galaxies . ... Next Section: HI in small elliptical . ... Several properties of elliptical galaxies appear to change at an absolute magnitude around M Large elliptical galaxies (defined here as those with M brighter than -19) are usually dominated by an old stellar population (e.g. Bressan et al. 1996), and have most of their gas in a hot X-ray corona (Forman et al. ...

... Armagh Planetarium . ... Universe . ... Posted on April 19, 2012 | ... Continue Reading.. ... 2 Comments In the upcoming weeks you will be hearing in the news the words тАЬDragon SpacecraftтАЭ, so Sinead McNicholl has the full story on what exactly this new vehicle is and [ ] . ... Posted on March 29, 2012 | 3 Comments The month of April is fantastic month for stargazing and for astronomy in general with numerous dates to mark in your calendar. €аFrom Earth Day celebrated on 22 April, in [ ] . ...

... There has been a heated public discussion in the past few years about whether our ninth planet is really deserving of the name. Since Pluto orbits a star, and is much less luminous, it certainly satisfies the definition we have above. The problem is actually not with Pluto, but with a very large number of other bodies in our Solar System which also satisfy this definition, but which are not called planets. Perhaps the most notable of these is Ceres, the largest asteroid. ... Planet . ...

... Earth is the tiny spot between Jupiter and the Sun). ... Distance Radius Mass Name Orbits (000 km) (km) (kg) --------- ------- -------- ------- ------- Sun 697000 1.99e30 Jupiter Sun 778000 71492 1.90e27 Saturn Sun 1429000 60268 5.69e26 Uranus Sun 2870990 25559 8.69e25 * Neptune Sun 4504300 24764 1.02e26 * Earth Sun 149600 6378 5.98e24 Venus Sun 108200 6052 4.87e24 Mars Sun 227940 3398 6.42e23 Ganymede Jupiter 1070 2631 1.48e23 + Titan ... Extrema .. ...

You Can Make Stellar Images Brighter . Articles | ... A few months ago I wrote an article titled "You Can’t Make Them Brighter". So why am I now writing that you can make them brighter. ... The image of a focused star is actually a small disk called the Airy disk, named after the 19 th century scientist Sir George Airy. ... For a given aperture, a smaller Airy disk means that the light is focused to a smaller disk and is therefore brighter. ... www.astronomy.net . About Astronomy Net | ...

... The WFPC2 CCDs have a small b ut significant charge transfer efficiency (CTE) problem which causes some signal to be lost when charge is transferred down the chip during readout. This has the effect of making objects at higher row numbers (more charge transfers) appear fainter than they would if they were at low row numbers. The effect depends on the temperature of the CCDs. ... It is also possible that proportional losses for fainter stars, at least with no background, may be larger. ...

... self-absorption - the absorption of light shining on an object by a process similar to that which produced the light originally; if a cloud emits less light than it absorbs from other clouds behind it, this net loss of light, termed self-absorption , causes the foreground cloud to appear darker than the background field (the term is from spectroscopy, where small absorption dips sometimes occur in larger emission lines, making the latter look as if it is absorbing part of itself) . ... HISA Main ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... The Perseid meteor shower, which this year peaked around midnight on the evening of August 12th, will continue at a low rate until around August 24th. ... Video clips in AVI and mp4 formats of some of the brightest Perseid meteors detected by the ObservatoryтАЩs cameras together with an image illustrating the parallel tracks in space of the Perseid meteors detected at Armagh can be found here . ...

Next: *imcopy* - Compress an Up: Image Manipulation Previous: Image Manipulation . input file: rp90_a.imh . ... xr> images # need this package im> imcopy rp90_a[200:263,282:345] rp90_aa # extract 64x64 region from .imh file rp90_a[200:263,282:345]-->rp90_aa . ... As an example we make an input file for the smoothing task which needs small arrays or it takes too long to run. im> imcopy xdata$rp110590.qp[6830:7029,9290:9489] rp90_ab.imh # extract 200x200 region from the .qp file . ...

Next: Ejectors in Massive Binary Previous: Artificial Galaxy: Full Matrix . The first version of the Scenario Machine was aimed especially at the simulation of massive binary star evolution. ... First, there is a large class of intermediate mass binaries (say, consisting initially of 8 + 5 solar masses) that can also produce NS and thus lead to the formation of a bright X-ray source. ... Next: Ejectors in Massive Binary Previous: Artificial Galaxy: Full Matrix Mike E. Prokhorov . ...

... Astrophysics Group . ... AMI Local Resources . ... AMI Day . ... AMI Small Array Webcam . AMI Large Array Webcam . Small Array Status , Monitor data ? ... Large Array Status , Monitor data ? ... Phase-switch-related electronics appear in the Control Electronics page below) . ... Technical meeting minutes (files listed as YYMMDD) . Science meeting minutes . Data reduction meeting minutes (files listed as YYMMDD) . ... Archive Minutes (2000-2005): Technical meeting minutes | ...

Estimating the NEO Population and Impact Risk: Past, Present and Future . ... Since most of the risk resides in the largest impactors, finding that fraction of the largest bodies, and that none of them has a significant chance of impacting in the next century or so, "retires" more than 90 % of the impact risk, including most of the risk of a globally catastrophic impact event. ... In the mid-size range, from ~150 m to ~1 km, the main risk is from tsunami generated by an ocean impact. ...

... Spherical aberration, coma, and astigmatism are also easily observed using the star test. ... Off-axis images are complex. ... Fig. ... Diffraction by a circular aperture as a function of defocus for no aberration Airy Disk 1 wave defocus Less than 1 wave defocus Fig. ... Diffraction by a circular aperture as a function of defocus for third-order spherical aberration Paraxial Focus Small distance inside paraxial focus Moderate distance from marginal focus Immediate neighborhood of marginal focus Fig...